The present research proposal aims to expand upon substantial initial progress made toward clarifying the biochemical ontogeny of development of the secondary palate. Differentiation of the palate may be defined in terms of glycosaminoglycan, collagen, cyclic nucleotide and prostaglandin synthesis. Beta-adrenergic receptor occupancy also appears to play a significant role in palatal development. We, therefore, propose (1) to characterize the Beta-adrenergic receptor system and a prostaglandin receptor system in the developing murine secondary palate by receptor-radioactive ligand competitive binding assays; (2) investigate factors regulating properties of these receptor systems in vitro using primarily cAMP radioimmunoassay; (3) determine involvement of catecholamines in qualitative and quantitative synthesis of palatal extracellular glycosaminoglycans, collagen and cell proliferation using cellulose acetate and polyacrilamide gel electrophoresis and collagen types I and III radioimmunoassay; and (4) determine hormonal responsiveness of palatal epithelium following heterospecific epithelial-mesenchymal recombination.